Substrate processing apparatuses are used to subject various types of substrates such as semiconductor substrates, substrates for liquid crystal displays, plasma displays, optical disks, magnetic disks, magneto-optical disks, and photomasks, and other substrates to various types of processing.
Such a substrate processing apparatus generally subjects a single substrate to a plurality of different types of processing successively. The substrate processing apparatus as described in JP 2003-324139 A comprises an indexer block, an anti-reflection film processing block, a resist film processing block, a development processing block, and an interface block. An exposure device is arranged adjacent to the interface block as an external device separate from the substrate processing apparatus.
In the above-mentioned substrate processing apparatus, a substrate carried out of the indexer block is transported to the exposure device through the interface block after being subjected to anti-reflection film formation and resist film coating processing in the anti-reflection film processing block and the resist film processing block. After the resist film on the substrate is subjected to exposure processing in the exposure device, the substrate is transported to the development processing block through the interface block. After the resist film on the substrate is subjected to development processing to form a resist pattern thereon in the development processing block, the substrate is transported to the indexer block.
With recent increases in density and integration of devices, making finer resist patterns has become an important problem. Conventional exposure devices have generally performed exposure processing by reduction-projecting a reticle pattern on a substrate through a projection lens. With such conventional exposure devices, however, the line width of an exposure pattern is determined by the wavelength of a light source of the exposure device. Therefore, making finer resist patterns has had a limitation.
Therefore, an immersion method is suggested as a projection exposure method allowing for finer exposure patterns (see, e.g., WO99/49504 pamphlet). In a projection exposure device according to the WO99/49504 pamphlet, an area between a projection optical system and a substrate is filled with a liquid, resulting in a shorter wavelength of exposure light on a main surface of the substrate. This allows for finer exposure patterns.
In the projection exposure device according to the above-mentioned WO99/49504 pamphlet, however, exposure processing is performed with the substrate and the liquid brought into contact with each other. When a contaminant adheres to the substrate before the exposure processing, the contaminant is mixed into the liquid.
Although the substrate is subjected to various types of film formation processing before the exposure processing, an edge of the substrate may, in some cases, be contaminated in the process of the film formation processing. When the substrate is subjected to the exposure processing with the edge of the substrate thus contaminated, a lens of the exposure device may be contaminated, resulting in a defective dimension and a defective shape of an exposure pattern.